The ‘flags’ (really coat of arms) for the Norwegian
counties have all, except for Oslo county, been taken
from the official graphic profiles of the counties.
They were then converted to PNG files with a common
height (200 pixels).

The coat of arms for Oslo county have been taken from
Wikimedia Commons (downloaded on 2018-08-27):
https://commons.wikimedia.org/wiki/File:Oslo_komm.svg